Microbes and methods for producing 1-propanol

Abstract

Provided herein are microbes metabolically engineered to produce 1-propanol from a 1,2-propanediol intermediate. The microbes may include one or two pathways for production of 1-propanol from a 1,2-propanediol intermediate. Also provided herein are methods for using the microbes for the production of 1-propanol.

What is claimed is: 
     
         1 . A microbe metabolically engineered to comprise at least one metabolic pathway for the production of 1-propanol from a 1,2-propanediol intermediate. 
     
     
         2 . The microbe of  claim 1  which produces 1-propanol using glucose as a carbon source. 
     
     
         3 . The microbe of  claim 1  metabolically engineered to overexpress an enzyme having methylglyoxal synthase activity. 
     
     
         4 . The microbe of  claim 1  metabolically engineered to overexpress an enzyme having secondary alcohol dehydrogenase activity. 
     
     
         5 . The microbe of  claim 5  wherein the secondary alcohol dehydrogenase comprises a diol dehydrogenase. 
     
     
         6 . The microbe of  claim 1  metabolically engineered to overexpress an enzyme having primary alcohol dehydrogenase activity. 
     
     
         7 . The microbe of  claim 6  wherein the enzyme having primary alcohol dehydrogenase activity comprises a methylglyoxal reductase. 
     
     
         8 . The microbe of  claim 6  wherein the enzyme having primary alcohol dehydrogenase comprises a lactaldehyde reductase. 
     
     
         9 . The microbe of  claim 6  wherein the primary alcohol dehydrogenase is native to the microbe. 
     
     
         10 . The microbe of  claim 1  comprising a first vector comprising a polynucleotide encoding at least one enzyme in a 1,2-propanediol pathway, the enzyme selected from one having methylglyoxal synthase activity, one having secondary alcohol dehydrogenase activity, and one having primary alcohol dehydrogenase activity. 
     
     
         11 . The microbe of  claim 10  wherein the first vector encodes methylglyoxal synthase, a methylglyoxal reductase, and a diol dehydrogenase. 
     
     
         12 . The microbe of  claim 10  wherein the first vector encodes an enzyme having methylglyoxal synthase activity and an enzyme having secondary alcohol dehydrogenase activity, wherein the enzyme having secondary alcohol dehydrogenase activity is a diol dehydrogenase or a glycerol dehydrogenase. 
     
     
         13 . The microbe of  claim 10  wherein the first vector encodes an enzyme having methylglyoxal synthase activity, an enzyme having secondary alcohol dehydrogenase activity, and an enzyme having primary alcohol dehydrogenase activity, wherein the enzyme having secondary alcohol dehydrogenase activity is a diol dehydrogenase or a glycerol dehydrogenase, and wherein the enzyme having primary alcohol dehydrogenase activity is a lactaldehyde reductase. 
     
     
         14 . The microbe of  claim 1  comprising two metabolic pathways for the production of the intermediate, 1,2-propanediol. 
     
     
         15 . The microbe of  claim 1  metabolically engineered to overexpress an enzyme having diol dehydratase activity. 
     
     
         16 . The microbe of  claim 15  wherein the enzyme having diol dehydratase activity is selected from a propanediol dehydratase and a glycerol dehydratase. 
     
     
         17 . The microbe of  claim 1  metabolically engineered to overexpress an enzyme having 1-propanal reductase activity. 
     
     
         18 . The microbe of  claim 1  which is a prokaryotic cell. 
     
     
         19 . The microbe of  claim 18  which is an  E. coli  cell. 
     
     
         20 . The microbe of  claim 19  wherein the  E. coli  cell comprises an enzyme having primary alcohol dehydrogenase activity, wherein the primary alcohol dehydrogenase is a lactaldehyde reductase, and wherein the lactaldehyde reductase is native to the prokaryotic cell. 
     
     
         21 . The microbe of  claim 20  wherein the  E. coli  cell comprises an enzyme having primary alcohol dehydrogenase activity, wherein the primary alcohol dehydrogenase is a lactaldehyde reductase, and wherein the lactaldehyde reductase is heterologous to the prokaryotic cell. 
     
     
         22 . The microbe of  claim 20  wherein the  E. coli  cell comprises an enzyme having primary alcohol dehydrogenase activity, wherein the primary alcohol dehydrogenase is a 1-propanal reductase, and wherein the 1-propanal reductase is native to the prokaryotic cell. 
     
     
         23 . The microbe of  claim 20  wherein the  E. coli  cell comprises an enzyme having primary alcohol dehydrogenase activity, wherein the primary alcohol dehydrogenase is a 1-propanal reductase, and wherein the 1-propanal reductase is heterologous to the prokaryotic cell. 
     
     
         24 . A method for producing 1-propanol comprising culturing the microbe of  claim 1  under conditions suitable to produce 1-propanol 
     
     
         25 . The method of  claim 24  further comprising isolating the 1-propanol. 
     
     
         26 . The method of  claim 24  comprising culturing the microbe in low phosphate media. 
     
     
         27 . The method of  claim 24  comprising culturing the microbe under anaerobic conditions.